Method Of Providing Superelevation
Introduction of superelevation on a horizontal curve of a road is an important feature in road construction. Superelevation is provided in the following two methods.
- Elimination of the crown of the cambered section.
- Rotation of pavement to attain full superelevation.
Read More: Purposes of Providing Superelevation
1. Elimination of The Crown of The Cambered Section
In this method, the outer half of the camber is gradually decreased. This may be done by two methods.
In the first method, the outer half of the camber is rotated about the crown at the desired rate such that the surface falls on the same plane as the inner half.
In the second method, the crown is progressively shifted outwards. This method is not usually adopted.
2. Rotation of Pavement To Attain Full Superelevation
In this stage, superelevation is gradually provided over the full width of the carriageway so that the required superelevation is available at the beginning of the circular curve. The different method employed for attaining the superelevation is as follows:
A. Revolving Pavement About The Center Line
In this method the surface of the road is rotated about the center line of the carriageway, gradually lowering the inner edge and rising the upper edge. The level of the center line is kept constant. This method is widely used.
B. Revolving Pavement About The Inner Edge
In this method, the surface of the road is rotated about the inner edge, raising the center and outer edge.
C. Revolving Pavement About The Outer Edge
In this method, the surface of the road is rotated about the outer edge depressing the center and inner edge.
- 1 Method Of Providing Superelevation